Unlike most papers, e.g., [1]}, [2]}, [3]}, that slice the network based on traffic variations in single time-scale, a few recent papers, e.g., [4]}, [5]}, [6]}, propose two-time scale frameworks to improve network management and efficiency of resource allocations. In [5]}, a two-time-scale resource management
scheme for network slicing in cloud RAN is proposed. Zhang et al. propose a long time-scale inter-slice resource reservation for slices and a short time-scale intra-slice resource allocation in [5]}. However, the formulation of [5]} does not consider the slice reconfiguration cost, which is non-continuous and non-convex [10]}, nor the resource reservation in the backhaul. Thus, [5]} fails to provide end-to-end QoS guarantees to users. A multi-time-scale decentralized online orchestration of software-defined networks is studied in [12]}, where a set of network controllers are activated based on the temporal and spatial variations in traffic requests. The slice activation and reconfiguration in a two time-scale framework are not studied in the existing literature; these topics comprise the main focus of this work.
